Leachate treatment with nitrification of ammonia

Abstract Results are presented on the treatment of leachate to remove ammonia by biological nitrification. Outdoor activated sludge and trickling filter pilot plants were operated for 2 years at a major co-disposal landfill. Leachate ammonia nitrogen concentrations ranged from 150 to 550 mg l−1 while TOC concentrations ranged from 200 to 500 mg l−1. Very little of the TOC was degradable and BOD: NH3-N ratios were typically 1:3. Nitrification was successfully established in both plants, and curves were established for the response of the kinetics to different temperatures. Maximum ammonia removal rate in the activated sludge plant was at least 131 g N kg VSS−1 day−1 achieved at an average temperature of 13°C. Maximum removal rate in the trickling filter was 309 mg N m−2 day−1, at 16°C. Operating problems and strategies for full-scale treatment are discussed.